1. Field of the Invention
The present invention relates to an apparatus and method for post-processing a dialogue error in a speech dialogue system using multilevel verification, and more particularly, to an apparatus and method for recognizing various dialogue errors that may occur in a speech dialogue system through multilevel verification and efficiently performing post-processing of the dialogue errors.
2. Discussion of Related Art
Speech recognition technology refers to apparatuses and methods for analyzing human speech by a speech recognition machine to recognize or understand the recognized results, and the technology is applied to various areas such as telephone dialing, user identification, and control of electronic appliances.
However, generally, speech is uttered in a poor environment caused by various static and noise, and thus it is very difficult for the speech recognition machine to exactly recognize the speech to output the recognized results.
Accordingly, since the output of the currently implemented speech recognition machine usually includes errors to some extent, errors should be detected from speech recognition results amend them before final speech recognition results are output in order to apply the output to a substantial system.
Meanwhile, in methods for minimizing the errors, a method of outputting final speech recognition results by user confirmation and correction with respect to multiple values of speech recognition is disclosed in U.S. Patent No. 2006/0247931, entitled “Method and Apparatus for Multiple Value Confirmation and Correction in Spoken Dialog Systems (published Nov. 2, 2006)”. Also, a method of determining speech recognition errors by combining reliability with respect to speech recognition results and reliability of mapping from user intent is disclosed in U.S. Patent No. 2006/0149544 entitled “Error Prediction in Spoken Dialog Systems (published Jul. 6, 2006)”.
In addition, a method, in which erroneous portions and error types are exactly recognized through the steps of word error verification, utterance verification and slot-value verification, is disclosed by Sangkeun Jung, Cheongjae Lee and Gary Geunbae Lee in “Three Phase Verification for Spoken Dialog Clarification”, International Conference on Intelligent User Interfaces, 2006. Furthermore, a method, in which errors are recognized using an acoustic confidence score based on object-based approach to verify the whole utterance, and after a dialogue is completed, or a user's previous utterance is arranged to be finally verified by the user, so that errors are recognized to be corrected, is disclosed in the paper by Michael McTear, Ian O'Neill, Philip Hanna and Xingkun Liu, “Handling Errors and Determining Confirmation Strategies—An Object-Based Approach”, IEEE Transactions on Speech and Audio Processing, Vol. 45, No. 3, pp. 249-269, 2005.
However, in the conventional methods, errors in a current sentence uttered by a user are acoustically detected to correct the detected errors by a user's verification or selection, and since the speech recognition errors are detected without taking into account the whole dialogue, the user has to verify the detected errors.